A maladaptation is an adaptation that is (or has become) less helpful than harmful. It is a term used when discussing both humans and animals in fields such as evolutionary biology, biology, psychology (where it applies to behaviors and other learned survival mechanisms) and other fields where adaptation and responsive change may occur. Like adaptation, it may be viewed as occurring over geological time, or within the lifetime of one individual or a group.

It can also signify an adaptation that, whilst reasonable at the time, has become less and less suitable and more of a problem or hinderance in its own right, as time goes on. This is because it is possible for an adaptation to be poorly selected or become less appropriate or even become on balance more of a dysfunction than an positive adaptation, over time.

Examples:

During periods of climate change, such as global warming or cooling, species that were well adapted in the original climate may be maladapted to the new climate and die out.

Resistance to antibiotics may be seen as an adaption/maladaption issue from the point of view of infective agents: the initial disease agents are well adapted to the human body, hence the disease is initially successful. When the person takes antibiotics, the body chemistry (the environment within which the agents must live and succeed) becomes more hostile, and only those which are more than averagely adapted to antibiotics will survive. The rest are maladapted to this new chemistry, and die.

Screaming for attention may be a successful adaptation for a child with an over-attentive mother, however if it is continued as a strategy as an adult it is likely to be maladaptive and less successful in normal adult society or within a relationship.